Question

addition & subtraction – least # of decimal places/digits behind the decimal multiplication & division – least # of significant figures 13. how many significant figures are in the measurement 375.20 g? 14. which value does not have three significant figures? a. 301 sec. b. 0.00290 m c. 120 ml d. 5,280 mi 15. convert 3.009 × 10²² atoms of zinc to moles of zinc. represent your final answer with the correct number of significant figures. 16. find the sum of the following measurements: 1.90 m, 0.318 m, and 5.6 m. represent your final answer with the correct number of significant figures. 17. true or false: defined quantities such as 60 s/min and 22.4 l/mol can be considered when determining the number of significant figures in a value.

Explanation:

Step1: Count significant figures

For 375.20 g: non-zero digits (3,7,5,2) are significant; trailing zero after decimal is significant. Total = 5.

Step2: Identify 3-significant-figure value

Check each option:

• A. 301 sec: 3 sig figs
• B. 0.00290 m: 3 sig figs
• C. 120 mL: 2 sig figs (trailing zero no decimal)
• D. 5,280 mi: 3 sig figs

Step3: Convert atoms to moles

Use Avogadro's number $N_A=6.022\times10^{23}\text{ atoms/mol}$.
$n=\frac{3.009\times10^{22}\text{ atoms}}{6.022\times10^{23}\text{ atoms/mol}}$
$n=\frac{3.009}{60.22}\text{ mol}=0.04997\text{ mol}\approx0.0500\text{ mol}$

Step4: Sum measurements with sig figs

Add values: $1.90 + 0.318 + 5.6 = 7.818$ m. Round to least decimal places (1 from 5.6).

Step5: Evaluate defined quantities sig figs

Defined quantities have infinite sig figs, so they don't limit count.

Answer:

1. 5
2. C. 120 mL
3. $0.0500$ mol
4. $7.8$ m
5. True